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UniProt functional annotation for Q9FZN8 | ||
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| UniProt code: Q9FZN8. |
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| Organism: | |
Camellia sinensis (Tea). |
| Taxonomy: | |
Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae; asterids; Ericales; Theaceae; Camellia. |
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| Function: | |
Involved in the biosynthesis of caffeine (PubMed:10984041, PubMed:16333668, PubMed:26773541, PubMed:30303011, PubMed:25133732). Catalyzes the conversion of 7-methylxanthine (7mX) to theobromine and of theobromine to caffeine (PubMed:10984041, PubMed:16333668, PubMed:26773541, PubMed:30303011, PubMed:25133732). Has 3-N- and 1-N- methylation activity (PubMed:10984041, PubMed:16333668). {ECO:0000269|PubMed:10984041, ECO:0000269|PubMed:16333668, ECO:0000269|PubMed:25133732, ECO:0000269|PubMed:26773541, ECO:0000269|PubMed:30303011}. |
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| Catalytic activity: | |
Reaction=7-methylxanthine + S-adenosyl-L-methionine = H(+) + S- adenosyl-L-homocysteine + theobromine; Xref=Rhea:RHEA:24604, ChEBI:CHEBI:15378, ChEBI:CHEBI:28946, ChEBI:CHEBI:48991, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789; EC=2.1.1.160; Evidence={ECO:0000269|PubMed:10984041, ECO:0000269|PubMed:16333668, ECO:0000269|PubMed:26773541, ECO:0000269|PubMed:30303011}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:24605; Evidence={ECO:0000269|PubMed:10984041, ECO:0000269|PubMed:16333668, ECO:0000269|PubMed:26773541}; |
| Catalytic activity: | |
Reaction=S-adenosyl-L-methionine + theobromine = caffeine + H(+) + S- adenosyl-L-homocysteine; Xref=Rhea:RHEA:20944, ChEBI:CHEBI:15378, ChEBI:CHEBI:27732, ChEBI:CHEBI:28946, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789; EC=2.1.1.160; Evidence={ECO:0000269|PubMed:10984041, ECO:0000269|PubMed:16333668, ECO:0000269|PubMed:26773541, ECO:0000269|PubMed:30303011}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:20945; Evidence={ECO:0000269|PubMed:10984041, ECO:0000269|PubMed:16333668, ECO:0000269|PubMed:26773541}; |
| Catalytic activity: | |
Reaction=1,7-dimethylxanthine + S-adenosyl-L-methionine = caffeine + H(+) + S-adenosyl-L-homocysteine; Xref=Rhea:RHEA:10280, ChEBI:CHEBI:15378, ChEBI:CHEBI:25858, ChEBI:CHEBI:27732, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789; EC=2.1.1.160; Evidence={ECO:0000269|PubMed:10984041, ECO:0000269|PubMed:16333668}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:10281; Evidence={ECO:0000269|PubMed:10984041, ECO:0000269|PubMed:16333668}; |
| Cofactor: | |
Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000250|UniProtKB:Q9FLN8}; Note=Binds 1 Mg(2+) ion per subunit. {ECO:0000250|UniProtKB:Q9FLN8}; |
| Biophysicochemical properties: | |
Kinetic parameters: KM=24 uM for paraxanthine {ECO:0000269|PubMed:10364410, ECO:0000269|PubMed:12527364, ECO:0000269|PubMed:12860386}; KM=186 uM for 7-methylxanthine {ECO:0000269|PubMed:10364410, ECO:0000269|PubMed:12527364, ECO:0000269|PubMed:12860386}; KM=344 uM for theobromine {ECO:0000269|PubMed:10364410, ECO:0000269|PubMed:12527364, ECO:0000269|PubMed:12860386}; KM=21 uM for S-adenosyl-L-methionine {ECO:0000269|PubMed:10364410, ECO:0000269|PubMed:12527364, ECO:0000269|PubMed:12860386}; pH dependence: Optimum pH is 8.5. {ECO:0000269|PubMed:10364410, ECO:0000269|PubMed:12527364, ECO:0000269|PubMed:12860386}; |
| Pathway: | |
Alkaloid biosynthesis. {ECO:0000269|PubMed:10984041}. |
| Tissue specificity: | |
Expressed in young leaves and flowers. {ECO:0000269|PubMed:20469645}. |
| Developmental stage: | |
Expression declines during leaf development but remains constant throughout the flower development. {ECO:0000269|PubMed:20469645}. |
| Induction: | |
Down-regulated by drought. {ECO:0000269|PubMed:20469645}. |
| Biotechnology: | |
Saccharomyces cerevisiae (Yeast) expressing Coffea arabica (coffee) xanthosine methyltransferase (CaXMT1) and Camellia sinensis (tea) caffeine synthase (TCS1) accumulates caffeine. {ECO:0000269|PubMed:25133732}. |
| Similarity: | |
Belongs to the methyltransferase superfamily. Type-7 methyltransferase family. {ECO:0000305}. |
Annotations taken from UniProtKB at the EBI.